As you may or may not have seen in your local surf shop, a magazine, the internet, the G-CURVE fin set is about $80-100. It is the best fin system I have ever experienced. Ive tried K fins and what not, but the G-CURVE system is incredible.
It comes in 3 carbon fibre pieces. The trailer fin is large and bulky which is perfect for larger waves. The curved fins are really do the magic. Theyre light and sturdy which you can feel in the water.
The main benefit from the curved fins is a gain in speed. I surf NJ and SC, USA and the waves are usually small, so speed is extremely difficult to achieve with standard, stock fins.
EDIT: I use a G3 (i believe its called this. its the smallest trailer made for FCS) with G-CURVES on my rails. The small trailer is easier to whip the tail on mush waved.